I. Field of the Invention
The present invention relates generally to feed devices and, more particularly to such a device for sequentially feeding workpieces to the work performing area of a lathe.
II. Description of the Prior Art
Lathes are used for machining a wide variety of articles of manufacture. Typically the lathe includes a tailstock spindle which clampingly engages one axial end of a workpiece and a headstock spindle which clampingly engages the other axial end of the workpiece. The lathe further includes means for rotatably driving one or both of the spindles so that the workpiece rotates in unison with the spindles while suitable machining means perform the desired machining operation on the workpiece. The machining means can comprise, for example, cutting blades, a grinding wheel, and the like.
In order to completely machine many types of workpieces, for example, crankshafts for internal combustion engines, it has been the previous practice to perform two or more machining operations on sequential lathes in order to obtain the desired final or completed part. For example, conventionally, a crankshaft is initially subjected to a rough turn on a first lathe which rapidly removes stock from the workpiece on all surfaces concentric with the centerline of the workpiece. Thereafter, the crankshaft is moved to a subsequent lathe which performs a rough turning operation on the diameters that are not concentric with the centerline of the workpiece, as is well known in the art. Depending on the type of workpiece, the workpiece can undergo three, four and even more sequential machining operations on different lathes until the desired final part is obtained.
It has been the previous practice to either manually or automatically load and unload the workpieces into the work performing area of the lathe prior to each machining operation from the top or front of the lathe.
Automatic loading and unloading of the lathe from the top or front of the lathe involves a bulky and expensive overhead gantry type loader and unloader. These gantry type devices remove the finished workpiece from the lathe and insert the rough workpiece in the lathe. The gantry loader then transports the workpiece to a lift and carry conveyor located at the end of the lathe. The gantry loader deposits the finished workpiece on the conveyor and picks up a rough workpiece.
The loading and unloading of the workpiece from the top or front of the lathe, however, is disadvantageous due to the high equipment cost involved and these equipment costs are further increased when multiple sequential machining operations are required. Moreover, the actual automatic loading and unloading of the workpiece from the top or front to and from the lathe, respectively, often requires more time than the actual machining operation so that the lathe is utilized very ineffectively and inefficiently. In addition, excessive floor space is reduced.